diff options
| author | Mike Snitzer <snitzer@redhat.com> | 2018-09-26 03:56:02 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-10-13 10:18:55 +0300 |
| commit | 47c085c51d35e14d2e85aa10fa6f978b17ad6f9b (patch) | |
| tree | e78a4cbe8f65eccad43afffc86aa2f2ccc74e6a4 /drivers | |
| parent | 8bf0cc33eddc8d1c5267115f460a3bc4a714ea88 (diff) | |
| download | linux-47c085c51d35e14d2e85aa10fa6f978b17ad6f9b.tar.xz | |
dm cache: fix resize crash if user doesn't reload cache table
commit 5d07384a666d4b2f781dc056bfeec2c27fbdf383 upstream.
A reload of the cache's DM table is needed during resize because
otherwise a crash will occur when attempting to access smq policy
entries associated with the portion of the cache that was recently
extended.
The reason is cache-size based data structures in the policy will not be
resized, the only way to safely extend the cache is to allow for a
proper cache policy initialization that occurs when the cache table is
loaded. For example the smq policy's space_init(), init_allocator(),
calc_hotspot_params() must be sized based on the extended cache size.
The fix for this is to disallow cache resizes of this pattern:
1) suspend "cache" target's device
2) resize the fast device used for the cache
3) resume "cache" target's device
Instead, the last step must be a full reload of the cache's DM table.
Fixes: 66a636356 ("dm cache: add stochastic-multi-queue (smq) policy")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/md/dm-cache-target.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index c817627d09ca..58b97226050f 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -3390,8 +3390,13 @@ static dm_cblock_t get_cache_dev_size(struct cache *cache) static bool can_resize(struct cache *cache, dm_cblock_t new_size) { - if (from_cblock(new_size) > from_cblock(cache->cache_size)) - return true; + if (from_cblock(new_size) > from_cblock(cache->cache_size)) { + if (cache->sized) { + DMERR("%s: unable to extend cache due to missing cache table reload", + cache_device_name(cache)); + return false; + } + } /* * We can't drop a dirty block when shrinking the cache. |